They will work a set location the night it rains fairly well. The mud/water does not seem to bother them as much then/that night. The next day if it drys out a general rule of thumb is you what a dry set location. I'll re-bed with dry dirt or move the set. Note that is for best result and in my opinion.
However, I've seen both fox and coyotes sitting in flooded set locations. I've had set TOYALLY (underwater) flood set that I left to move later after they dry out. I've came back the next day and have a fox and/or yote sitting there as well.
I think the worst thing new trappers do is over lure, especially after a rain.
A flooded/wet set I would move to a dry location when the rest of the area is dry.
If the bed is filled with water and will or has not drained. And the ground is till wet. I'm moving the set if I cannot bed it correctly with dry dirt. Make the best set you can, in the locations you have, under the condition you've got. By doing short cuts you only cut your catch percentages.
"I've had set TOYALLY (underwater) flood set that I left to move later after they dry out. I've came back the next day and have a fox and/or yote sitting there as well."
after that rain about a week back, i had one sitting in a puddle. peat moss even floating on top a bit and touching it with a small stick you could tell there was about an inch of water sitting over my trap. i chuckled and figured no yote or anything will be touching that for a while, but knew it due time it'd eventually dry out. i liked its placement and 'feel' to it so i just let it ride for a week- nothing with the bed, no rescent or bait- just let it sit as is. apparently a dried out set blends itself nicely for yotes cause i was pleasantly surprised to see one bouncing when i came walking down the trail after it had dried itself out.
that whole not-screwing-with-sets takes a bit to get comfortable with. you'd think animals need lots of scent and fresh bait to get them interested in a set and the longer you leave it alone, the more it will 'die out' and become a wasted set, but once you start learning that not screwing with a set isnt laziness or uncaring but actually a strategic tactic, sometimes you learn something new.